Problem constructing an Array (after SQL statement)

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I'll me honest: its a ridiculous problem, I've spent more than hour because those 4 lines of code, but I cant think clearly, dont know if its because its 5550 am...

C#

cmd = new SqlCommand("Select Texto FROM Notes WHERE ID_users='" + id_user.ToString() + "'", conn);
          SqlDataReader dr = cmd.ExecuteReader();
          int num = 9; // static variable to change later
          string[] texto = new string[num];
         
               while (dr.Read())
               {
                   for (int i = 0; i < num; i++)
                   {
                       texto[i] = dr[0].ToString();
                   }
               }

So the problem is, the result from that SQL statement its simple 9 different strings. And I want to store them in Array - texto.

But for some (obvious) reason, all fields from array gets the same (the last result from sql query).

Can you please help me?

Posted 22-Dec-10 18:26pm

Maxdd 7

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3 solutions

Solution 2

C#

int i;
i=0;                     
                while (dr.Read())
                {
                  texto[i] = Convert.ToString(dr[0]);
                  i++;
                }

Used convert.ToString Beacuse if the string in dr[0] in null it will not through an exception otherwise it througs null pointer exception

Posted 22-Dec-10 18:38pm

Indresh1210

Solution 3

C#

for (int i = 0; i <= dr.RecordsAffected - 1; i++) {
    texto[i] = dr(0);
}

one more thing i would like to add is to use sql parameters to prevent sql injections :

for example:

cmd = new SqlCommand("Select Texto FROM Notes WHERE ID_users=@Iduser, conn);

C#

SqlParameter param = new SqlParameter();
param.ParameterName = "@Iduser";
param.Value = id_user.ToString();
param.Size = 15;
param.SqlDbType = System.Data.SqlDbType.VarChar;

cmd.Parameters.Add(param);

Cheers!

Posted 22-Dec-10 18:52pm

Tarun.K.S

Comments

fjdiewornncalwe 24-Dec-10 12:41pm

@Tarun: Good answer, but one suggestion that I give to devs in code reviews all the time. Keep statements as simple as possible. Where you write "i <= dr.RecordsAffected -1", it would be more efficient and easier to read if you just put "i < dr.RecordsAffected". It is a very minor thing, but cycles add up quickly if dr.RecordsAffected is very large. (This is really also just a hint to the OP. As a new dev this is something I would encourage him to pick up early)

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vivekse · Accepted Answer · 2010-12-22T18:31:00

Solution 1

Hi Maxxdd,

You are using nested loop here that is the problem. Remove for loop from there and declare i before while loop and increment i after assignment.

Posted 22-Dec-10 18:31pm

vivekse

Comments

Maxdd 7 23-Dec-10 0:36am

it worked like a charm. thank you so much :)

Maxdd 7 23-Dec-10 0:36am

for (i = 0; i < num; )
{
while (dr.Read())
{
texto[i] = dr[0].ToString();
i++;
}

}